Confirmed:
Charter Schools Beat the Daylights Out of Public Schools:
The cost of one bad teacher for one year on an average classroom of students is a whopping $266,000 in that class's collective lifetime earnings, which is over $2.6 million which that lousy teacher will cost society over ten years, or possibly $7.8 million over the teacher's tenure.
That's just one bad teacher. Multiply that by the possibly tens of thousands of wretchedly bad teachers whom the teachers' unions protect, and you realize the cost to society of our monopolistic public school system.